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Description

The slime star is pentagonal in shape and has a wide central disc and five stumpy arms with upturned tips. It grows to a diameter of about 15 centimetres (5.9 in) and has an inflated appearance as the entire aboral (upper) surface is covered by a thick, raised fleshy membrane. This has a smooth soft texture and is pale brown, grey, red or orange, often with a symmetrical darker pattern. It conceals the madreporite and scales on the aboral surface proper and the gap underneath it is filled with a spongy tissue. There is a central pore in this membrane allowing for water movement.[2][3] The arms have rows of fan-shaped groups of five to seven spines in between which are two rows of tube feet. There is a red eyespot surrounded by spines at the apex of each arm.[4]

Distribution and habitat

The slime star occurs in rocky areas on the west coast of North America from the Bering Sea southwards to central California at depths down to 950 metres (3,120 ft).[2] It is also known from the Aleutian Islands and Japan.[1] It is usually found in places where the current is strong.[4]

The slime star breeds in the summer, a female releasing a small number of eggs into the water. Nearby males then release sperm and the fertilised eggs rise to the surface of the water. They are bright orange or yellow and are wrapped in a gelatinous membrane. They become planktonic and pass through several developmental stages over the course of about twenty five days. They then undergo metamorphosis into juvenile starfish and settle onto the seabed.[3][4]